Flexible carbon fiber-based composites for electromagnetic interference shielding

With the rapid development of electronic information technology, the waste electromagnetic radiation generated by the wireless and various other electronic devices has caused serious harm to human health. The development of high-efficiency flexible electromagnetic interference (EMI) shielding materials has become one of the most effective ways to mitigate the increasingly serious problem of electromagnetic pollution. Flexible carbon fiber composites possess most of the physical requirements needed for EMI shielding applications, including high electrical conductivity, large specific surface area, light weight, flexibility, porous structure, and adjustable physical and chemical properties, and various morphology of carbon fibers-based composites applied EMI. In this review, the primary EMI shielding mechanism of carbon-fiber-based materials is presented. Since carbon fiber suffers from a low absorption efficiency when used for EMI shielding by itself, it is usually combined with additional EMI filling materials. Therefore, the methods of adding EMI filler materials to the carbon fiber framework and the influence of different fillers on the EMI shielding performance are also discussed. In addition, the novel structural designs of flexible carbon fiber-based EMI shielding materials, including fiber orientation, core–shell structure, and multilayer heterostructure, are summarized in terms of their classification, which includes composites with metal, polymer, nano-carbon, and MXenes. The review concludes with a brief discussion of the challenges, research directions, and future prospects of carbon-fiber-based EMI shielding materials.